Auto-oxidative process of recovering iodine from brines



March 8, 1932. F RANDOLPH 1,848,081

AUTO OXIIDATIVE PROCESS OF RECOVERING IODINE FROM BRINES Filed April '7, 1950 m-wane Ac.\0

4/ 42 Soon/M CHLOEIDE (EON Tuemwqs //v (/E/V Toe 40 heat and air as follows:

Patented Mar. 1, 1932 UN TED '3 FRANK x. RANDOLPH,; on LOS AneELEs, CALIFORNIA, .ASSIGNOR 'ro GENERAL'PSALT" is:

- oomrm, or LOS ANGELES, CALIFORNIA, a CORPORATION OF oAnrFoRNIA AUTO-OXIDATIVE rnoonssor nnoovnnmelonmnrnom Brunns Y Application lfiled April 7,

This invention has for its object the selective recovery of iodine from brinesof sub-r terranean origin, particularly those occurring 1n 011 wells. The process isnot confined to 5 oil-well brines,however, since it may equally Well be applied to any water containing any important. quantity 'of alkali-forming metal iodide, especially if I comparatively large 1, quantities of calcium and magnesium bicar- 1 bonates, or other alkali-earth metal bicarbo-.

nates are also present in the water.

I Afurther object of the invention is to provide and use a combined idodinecapturing and oxidizing agent, the exactnature of which will be later described, and, further,

to provide a process for eificiently regenerating such agent'and so providing acyclic process for the use of such agent. i

fBrieflyistated', my process is based upon the discoverythat the iodide andbicarbonate constituents of the natural brines of the kind described will react with a mixture of cuprous chloride and ferrous chloride in H such a way that the iodine is precipitatedas cuprous iodide in associ'ation with ferrous hydroxide; (I) 2NaI Ca'(HC0 lugmcoa 2 (Cu Cl 21 x01 v It ;is the ferrous hydroxidein the precipitate composed of cuprous iod de and ferrous hydroxide, -Wl11Ch will later, after ox dation to the ferric condit on, act as an oxldizing agent. I y i Excess copper from the cuprous chloride is preclpitated according to 'the equatlon (II) cu cifizreclz)+Fe=2cu+3rtec1 I i The precipitate from reaction (I) is oxidizedby the combined action of moisture,

- now treated with dilute'sulfuric acid for the purpose of separatin'gthe iodine. It in 1930. Serial No. 442,366.

this step that the oxidative area of the ferric," hydroxide in thejprecipitate isrealized, since otherwise, if it did' not occur, hydriodic acid would'be produced insteadbffree iodine. The equation is: 1 o, 1V) c1121, remen 6H2SO4+ heat= The regeneration of the combined iodinecapturingand oxidizing agent is easily acc'omplishedby means of ordinary salt and I o er as the following equation shows I 011 01, met) snazsoi not, the above'outline, it'will be evident either active or, abandoned, in the Vicinity Of Long Beach, California.v A typical; analysis I of this water as expressed in parts ,per million is: e

There are also present in this-water crude petroleum, dissolved 'naphthionic acids", frocolloidal clays of complex composition. 1

Partsper inillion 'tary inud'from drilling operationsandother view of anapparatus which I prefer to usex to carry out my process. Other apparatus may be substituted, but that shown allows the process to take place in a continuous manner, whlch is deemed essent al to commercial suces in the, drawing 1 is n inlet pipe for Oilwell' brine, this pipe delivering to amixing tank 2 above which is a tank 3 from which the combined precipitant and oxidizing agent may be delivered to the tank by a gravity discharge pipe in which there is a valve A. An agitator 5 is provided in the tank 2. A pipe 6 connects tank 2 and a deep settling tank 7 immediately adjacent which, is anothersettling tank 8 separated from tank 7 bya baflie wall 10. Tanks 7 and 8 possess conical'bottoms and deep battles 9 and 11 respectively, which extendnearly but not quite totheir bottoms. 'The battles are located oppositeand near the tank inlets and their tunetionis'to direct-the inflow and'minimize disturbance. An outlet pipe'12 connects the upper part of tank 8 with a maze-box 13 cont'aining; iron or steel turnings 14:, the function of which is to precipitate copper contained in the efiiuent water- An overflow pipe 15 fromthe-upperpart of maze-box 13 is provided tolead the overfiow of this box q a te.

1 On a levelabove the tops of tanks 7 and 8 is locatedthe remainder of the apparatus a sludge storage and filter tank 19 of which is in comn unication with tanks 7 and 8. Two Pip .7. l ex e m t bo m ta k 7 and r spectiv ly to a pump. 16. which isarrangedto discharge into tank 19. The latter isalso, providedwith two gravity dischargepipes 20. and 21, the first extending fromabove the. usual sludge level and the sec- 0nd from the filtrate compartment. These extend to tank 7 and are for the purpose of returning-excess water from tank 19 to the ecip i n a ks- U y a Fromtheregion of thesludge level in tank IQthereeXtendsa discharge pipe 22in which there a pump 23, the dischargleof the pump extending into a heatable pan 24 under which there is a burner 25.

On a still higher level is located the iodinesubliming apparatus. This comprises a still or retort 28 heated from below by a burner 31. A charging opening 27 is provided through which oxidized precipitate may be delivered from a conveyor 26 extending to pan 24, and sulfuric acid may be delivered from a tank 29 and valved pipe 30. A bottom discharge pipe 12 in which there is a valve 11 connects the bottom of the retort 28 with a second heatable pan 411 under which there is a burner 45. This pan is intended for the g n at n o th 0dine+ apturingand Z' g ag t Above the p n; two salt reservoirs 16 and 17 are mounted. A pipe 19 in which there-isapump 48Lextends from the interior of pan 1 1 through the region of the retortbur-ner flametothe precipitant storage n r a i From the top of retort 28 a stoneware conduit 32 extends, this terminating in a hopper 38 located above a fi'lter box 38. From the top ofhopper 33 there extends' a'spiral condensing pipe 35 contained'in a water jacket Supplied with cool water through an inlet 86. All outl'et is provided at'37. From the bottom of filter 38 extends a discharge pipe 40 in which there is a pump 3.9, the pipe being so arranged that water or acid iromthe filter maybe returned to the retort 28.

The operation of the process in the above described apparatus is as follows:

Brine flows continuously intothe mixing tank 2 from pipe 1, while precipitant also. flows from tankB ata rate just suflijcient to react with all of the iodine. The brine and precipitant are thoroughly mixed by agitator 5' after which the contents of tank 2, flow into tank 7 for settling. The fiowis turned by baflle 9 into the bottom of tank 7, where: upon considerable deposition of cuprous iodide and ferrous hydroxidetakes place according to Equation Mostof the solid matter remaining in suspension is removed by settling in tank 8, through which the water nextifldwsu When finally flows out overthe iron turnings in the maze-box 18, it deposits whatever copper'it carries on the iron, from which the copper may'ea'sily be recovered and; re-used in the'process. The water then flows to waste through pipe 15.

After a suitable period of operation, when considerable sludge or precipitate has collected in the conic'al'bottoms of tanks 7 and 8, pump 16 is'operate'dandthe sludge transferred to storage and filtertank: 19, the excess water being allowed to. return to, tank 7 through pipes 20 and21.;. W'henthesludge has reached a suitable consisten y intank 19, that is,,of a fairly fluid paste, it is pumped by means of pump 23. topan 24;. There it is heated with'accessfof air while still moist un it it i y. nd" he errous hydroxid therein fully oxidized to ferric hydroxide according to Equation (III) It is then transferred. by conveyor 26 to retort 28.

Sulfuric acid from tank 29-is now added in proper quantityto the oxidized sludge in the retort and the temperature is raised gradually to a point at which elemental iodine sublimes. The iodine vaporstraverse the earthenware pipe 32, gradually solidifying to scales therein, these scales being carried into hopper 33. 1' Vapors still remaining uncondensed in that V hopper rise through water cooled condenser 34 at the cooler temperature of which additional condensation takes place. All condensed products drop into filter box 38, in which the solid one (iodine) is separated from the liquids (water or dilute acid). The

'liquids are returned usually to the retort 28 by means of pump 39 and pipe 40.

The sublimation of iodine instead of hydriodic acid from the retort is due entirely V to the oxidizing action of the ferric hydroxide which acts according to Equation (IV). After this reaction is complete, the spent contents of the retort are discharged by gravity through pipe 42 intopan ttwhere suiticient salt and finely divided copper are added to satisfy Equation (V). The mass is then gently heated in the presence of water until the reagents present are entirely reduced'to the ous condition. The still Wet mass is then pumped by means of pump 4c8 and pipe 49, back to the precipitant storage tank 3.

It is evident that skilled chemists can. make considerable changes in this process Without departing from the spirit'of the invention. All such changes are to be regarded as lying within thescope of my invention.

I claim as my invention: 1

mixed iodine-precipitating agent into its original cuprous chloride and ferrous chloride by heating the residue of the acid decomposi tion with sodium chloride and copper in the presence of water until reduction issubstantially complete. I a

3. The process of recovering iodine from brines which contain alkali-metal iodides and alkali-earth metal bicarbonates, which comchlorideand ferrous chloride, allowing the V resulting precipitate to settle, periodically collecting the precipitate, oxidizing the precipitate containing cuprous iodide and ferrous hydroxide by heating in the presenceof air and moisture, decomposing the oxidized precipitate withsulfuric acid in the presence and. then condensing and collecting the iodine. i I

4. A process according to claim 3 having of heat whereby to separate elemental iodine,

the additional steps of treating the residue i from the separation of the iodine with suflicient sodium chloride and copper in the pres-.

ence of heat and moisture to producemixed cuprous chloride and ferrous chloride from the said residue, and then using the said mixed products to precipitate more iodine. V

In testimony whereof, I have hereunto setv my hand at Los Angeles, California, this 2nd day of April, 1930.

s FRANK K. RANDOLPH.

1. The process of recovering iodine from".

brines which contain it in combination with alkali-forming metals and which also con -v tain alkali-earth metal bicarbonates, which comprises precipitating the iodine, together with ferrous hydroxide by theaddition'of a mixture of cuprous chloride and ferrous chloride, separating the precipitate containing cuprous iodide and ferrous hydroxide from the bulk of the water, heating saidpreciptate f in the presence of oxygen sufficiently to cause the oxidation of the iron compound present to the ferric condition, and then treating the oxidized iron compound and the cuprous iodide with sulphuric acid at sufficiently high temperature to separate and volatilize elemental iodine.

2. The process of recovering iodine from duced elemental iodine, and regenerating the a brines containing it and alkali metal bicar- 

